If a bearing is heating and running at high temperature it is an indication that friction is being generated by the bearing. The friction could he caused by dirt or the bearing surface itself breaking down.  When the heat caused by the friction reaches a critical temperature the oil or the grease will lose its lubricating properties. The bearing’s condition will then quickly deteriorate until it is worn out.

But how can you tell when a bearing is running too hot – what is a good and quick bearing temperature check?  When I first started in milling I was told, that the best and quick way to check the temperature of a bearing was to spit on it, if it spit back it was too hot.

Our modern method isn’t much different, hold your hand on the base of the bearing.  Start counting. If your hand is still on the bearing by the time you reach the count of ten, then the bearing isn’t too hot.

In most concentrators, unless hot bearings are a frequent problem and there has been a procedure developed to handle them, a supervisor should be informed of the problem. It is his responsibility to determine the best way to correct the situation.